Line transferring device

ABSTRACT

Line transfer device as adapter for use with closed-head helicopter bundle block with pulling line sheave and conductor stringing sheave means coaxially mounted therein, and comprising line-receiving means supportingly connecting upper end of outer frame member and head bar and operable without disconnection therefrom to pass a line laterally from the exterior to the interior of the frame to enable such line placement from a helicopter, or the like. The line receiving means comprises a housing secured to the outer frame member and defining an arcuate trackway, a carrier wheel having circumferentially disposed bearings riding in the trackway, a bore eccentric to it and a peripheral line-receiving slot, straps depending from the head bar to support a pin extending through the bore, and latch and trigger mechanism pivoted on the head bar to cooperate with notch in carrier wheel to retain same with slot in active or linereceiving position and having trigger arm adjacent slot for movement by line introduced into slot to release latch to permit wheel to be rotated by the weight of the block to deliver line to interior of frame without disconnection of the frame. Also provided interiorly of frame are laterally extending guards pivoted at outer ends and springs holding them in inward position to prevent line engaging outer conductor stringing sheave means, which guards are swung out of the throat of the frame to inoperative positions by the running board as it passes through the frame to deposit the conductors attached thereto in the conductor stringing sheave means.

United States Patent Chadwick, Jr.

[111 3,905,581 14 1 Sept. 16, 1975 LINE TRANSFERRING DEVICE William H. Chadwick, Jr., Rossville, Ga.

Sherman & Reilly, Inc., Chattanooga, Tenn.

[22] Filed: Apr. 17, 1974 [21] Appl. No.: 461,505

[75] Inventor:

[73] Assignee:

52 us. c1 254/193; 254/197 51 Int. c1. ..B66D 1/36 [58] Field of Search 254/190 R, 193, 197, 192, 254/186 R, 134.3 PA; 24/115 R; 174/6 R;

Primary ExaminerFrank E. Werner Assistant Examinerl(enneth Noland Attorney, Agent, or FirmMcCa1eb, Lucas & Brugman [57] ABSTRACT Line transfer device as adapter for use with closedhead helicopter bundle block with pulling line sheave and conductor stringing sheave means coaxially mounted therein, and comprising line-receiving means supportingly connecting upper end of outer frame member and head bar and operable without disconnection therefrom to pass a line laterally from the exterior to the interior of the frame to enable such line placement from a helicopter, or the like. The line receiving means comprises a housing secured to the outer frame member and defining an arcuate trackway, a carrier wheel having circumferentially disposed bearings riding in the trackway, a bore eccentric to it and a peripheral line-receiving slot, straps depending from the head bar to support a pin extending through the bore, and latch and trigger mechanism pivoted on the head bar to cooperate with notch in carrier wheel to retain same with slot in active or line-receiving position and having trigger arm adjacent slot for movement by line introduced into slot to release latch to permit wheel to be rotated by the weight of the block to deliver line to interior of frame without disconnection of the frame. Also provided interiorly of frame are laterally extending guards pivoted at outer ends and springs holding them in inward position to prevent line engaging outer conductor stringing sheave means, which guards are swung out of the throat of the frame to inoperative positions by the running board as it passes through the frame to deposit the conductors attached thereto in the conductor stringing sheave means.

19 Claims, 8 Drawing Figures I 18 11 1 I i H11 o w ll. 11 l 2Q I 25 5 J7 'T21 23 lll ll/ 62 1" an"! q 5g R 5*59 11- 5 20- 1" W/ZO l ll 1| |||I 0 911 lllul. "INF/1 1 LINE TRANSFERRING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to stringing a plurality of high voltage conductors simultaneously and, more particularly, to adapters for closed-head bundle blocks for that purpose to receive the pilot or pulling line from a helicopter, or any aerial means, and transfer the line to the interior of the block.

2. Description of the Prior Art Known prior art helicopter stringing blocks employ an open-sided or cantilever frame structure in order to provide an opening through which a rope, such as a pilot or pulling line, may be introduced to the pulling line sheave from a helicopter or other aerial device. For example, U.S. Pat. No. 3,195,862 shows a simple helicopter stringing block having a single sheave, as does U.S. Pat. No. 3,479,014 in its modification of FIG. 3, and copending application for U.S. Pat. Ser. No. 420,953, filed Dec. 3, 1973, discloses an improved arrangement enabling depositing of a pilot or pulling line from a helicopter into a bundle block for use in simultaneously stringing two or more conductors. However, all of those prior devices necessitate using an open-sided or cantilever sheave frame and, especially in a bundle block having two or more coaxial sheaves, it would be more desirable to carry the loads imposed during conductor stringing with a closed frame.

SUMMARY OF THE INVENTION This invention provides means for enabling introduc tion of a rope, such as a pilot or pulling line, from a helicopter or other aerial means laterally into the pulling line sheave of a closed-head stringing block having a shaft supporting said sheave and inner and outer side frame members supporting the shaft and depending from a head bar, which is so operable without disconnecting the frame members from the head bar. This means is an adapter employable with existing closedhead blocks which comprises a housing and a carrier wheel interconnected with each other and between the head bar and the upper end of the outer frame member, with a peripheral slot in the wheel for receiving the line and carrying it into the interior of the frame during rotation of the wheel. Latch and trigger mechanism retains the carrier wheel in initial active position with the slot extending upwardly and outwardly and is released by a line moving laterally into the slot to permit such rotation of the wheel by the weight of the block. When used with a bundle block having conductor stringing sheave means rotatably supported on the shaft outwardly of the pulling line sheave, laterally extending guard means are pivotally mounted at their outer ends with their inner ends disposed interiorly of the frame and spring-urged to an inner position in the throat of the frame to prevent a line delivered by the linereceiving wheel from engaging the outer conductor stringing sheave means, the guards being swung outwardly to inoperative positions by the running board as it passes through the frame to deposit the conductors attached thereto in the conductor stringing sheave means.

In the drawings:

FIG. 1 is a rear elevational view of a bundle block embodying the features of the invention with the linereceiving means shown attached in active position;

FIG. 2 is a view similar to FIG. 1 showing the line deposited in the pulling line sheave and the block in normal working position;

FIG. 3 is a side view as seen from the right side of FIG. 1 on an enlarged scale;

FIG. 4 is a detail horizontal section taken substantially on the line 4-4 of FIG. 2 and using the same scale as FIG. 3-,

FIG. 5 is a detail vertical section through the carrier wheel of the line-receiving means in the active position of FIG. 1 on an enlarged scale and showing the lineactuated trigger in released position in broken lines;

FIG. 6 is a detail rear elevation on the same scale as FIG. 5 of the parts of the line-transferring device in the normal working position of FIG. 2;

FIG. 7 is a side view of the carrier wheel in active position, as seen from the right of FIG. 5, with a portion thereof in section; and

FIG. 8 is a detail elevation of the inner face of one of the two complemental housing members which together embrace thelower marginal portions of the carrier wheel.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, a closed-head helicopter conductor stringing block embodying the features of the invention is designated generally by reference numeral 11 and comprises inner and outer side frame members 12 suporting in any suitable manner the ends of a transversely extending shaft 13 shown in broken lines. The lower ends of side frame members 12 are rigidly secured to a bottom frame member 14. If desired, of course, the bottom frame member 14 need not be used, as this invention may be employed in any type of closed-head frame. The upper ends of the frame members 12 are shown as having the usual fittings 15 secured in any suitable manner, as by welding, which normally are pivotally secured, as by pins 16, to a head bar means 17 which preferably comprises laterally extending parallel members bolted together and adapted to be suspended in well-known manner by a socket connector 18, or the like, from the usual insulator means secured to a toweror supporting ground structure (not shown). Rotatably supported Within the frame on the shaft 13 are a centrally disposed pulling line sheave l9 and conductor stringing sheave means 20. It will be understood that such is the usual arrangement in conductor stringing blocks, and the line transferring device of this invention may be incorporated therein originally or as an adapter interposed between the side frame members 12 and the head bar 17 comprising strap means 21 pivotally connected at its upper end to head bar 17 and at its lower end by the pivot pin 16 to the fitting 15 on the inner side frame 12, and novel line-receiving means interconnected between the outer side frame 12 and the head bar means 17. This line-receiving means comprises a housing 22 secured to the outer side frame member 12 in any suitable way, a carrier wheel 23 rotatably interconnected therewith, and suspension means 24 depending from the head bar means 17 for rotatably supporting the wheel 23. Secured in any desired manner at its lower ends and extending upwardly and outwardly from the housing 22 is an outrigger arm 25 for receiving a rope 26, such as a pilot or pulling line, from a helicopter or other aerial device and directing the same into contact with the carrier wheel 23.

As best seen in FIGS. 3, 5, 6 and 8, the housing 22 is made up of two complementary parts secured together in parallel relationship, as by spacer means comprising aligned apertures 27 and sleeved bolts 28, and each part may be provided with other apertures 29 for receiving the lower ends of the outrigger 25. Each part of housing 22 is formed at its upper portion with an arcuate groove 31 in its inner surface and an outer arcuate recess 32 separated therefrom by an arcuate rib 33 (FIG. 8) which extends inwardly from the bottoms of groove 31 and recess 32 a shorter distance than the inner surface of the part. When these complementary parts are assembled and secured together, the groove 31 and its associated rib 33 define an arcuate trackway for one end of two sets of rollers 34 rotatably mounted in the carrier wheel 23. With the parts in their active positions of FIGS. 1 and 5, these two sets of rollers 34 comprise an upper inactive group of four and a lower then active group of five spaced peripherally of the wheel from each other. The outer ends of the group of five rollers 34 are there actively engaging the two arcuate ribs 33 of the housing 22. As best seen in FIGS. and 7, the carrier wheel 23 has an annular groove 35 in each side face and the several rollers 34 are rotatably mounted in suitable apertures 36 (FIG. 7) and retained in the wheel by rings 37 secured to the wheel by screws 38 (FIGS. 5 and 6) or any other suitable retaining means. The peripheral flanges on the carrier wheel 23 (defined by the annular grooves 35) and the ends of the rollers 34 are accomodated by the arcuate grooves 31 in the two parts of the housing 22 to enable relative rotational movements of the wheel 23 and the housing 22, the rollers 34 thus comprising circumferentially disposed bearing means cooperating with the trackway defined by the grooves 31.

As best seen in FIG. 5, the carrier wheel 23 has 21 peripheral slot 39 extending inwardly between the two sets of rollers 34 for receiving the line 26 in a manner later to be described. Eccentrically disposed relative to the rollers or bearing means 34 and the center of the carrier wheel 23 is a bore extending through the latter for receiving a sleeve 41 rotatable on a bolt or pin 42. Each end of the latter is carried by the lower end of a suspension strap comprising the suspension means 24 similarly rotatably supported adjacent its upper end by a sleeve 43 and a bolt or pin 44 extending through the head bar means 17 of the frame 11.

Latch and trigger mechanism is provided for retaining the carrier wheel in its active position of FIGS. 1 and 5 with the line-receiving slot 39 extending upwardly and outwardly of the frame 11 which includes a trigger or arm 45 pivotally mounted at 46 at its upper end on the head bar means 17 and having its lower end traversing the slot 39. The trigger 45 preferably comprises two such arms, one at each side of the wheel 23, interconnected at their upper ends and carrying a detent or rod 47 extending between them and disposed adjacent and inwardly of the pivot 46. This rod or detent 47 has a sleeve or roller 48 rotatably mounted thereon which cooperates with a peripheral notch 49 in the carrier wheel 23. The sleeve 48 being free to rotate on the detent 47, the same may more readily be moved upwardly out of the notch in wheel 23 when a line 26 is dropped into the slot 39 in a manner later to be described against the lower portions of trigger arms 45.

However, since the entire block is subjected to some vibrations during use, it is preferred to mount a coil spring 51 on the pivot 46 with one end engaging the end of a head bar 17 and its other end engaging the upper edge of an arm 45 to urge the detent resiliently into the slot 49 to afford sufficient resistance to prevent the trigger from being unlatched accidentally by vibrations of the parts. 1

The operation of the instant helicopter conductor stringing block now will be described. When hung by means of the connector 18 from a tower-supported in sulator in well-known manner, the carrier wheel 23 will be latched in its active position of FIGS. 1 and 5 by means of detent 47, 48 being engaged in notch 49. In that position, the peripheral slot 39 in the wheel 23 will be aligned with the outrigger 25 so that a pulling line 26 payed out from a helicopter or other aerial device onto the outrigger arm will slide downwardly by gravity into the slot 39 to trip the trigger 45 and release its detent 47, 48 from the notch 49 in wheel 23. Such release of the wheel from its latched active position will permit it to be rotated in a clockwise direction by that part of the weight of the block being suspended by the parts 22-24 from its position of FIGS. 1 and 5 to that of FIGS. 2 and 6 to carry the line 26 through this linereceiving means and into the interior of the closedhead block 11 without any disconnection of the frame. This is permitted because of the pivoted strap means 21 and because the axis of the bolt 42 of the suspension means 24 initially is disposed to the left or inwardly of a line through the centers of the upper suspension bolt 44 and the wheel 23. In other words, a major portion of the weight of the block 11 will be pulling downwardly through the agency of the housing 22 and rollers 34 of the group then engaging the rib 33 to extend the toggle comprising the suspension means 24, the wheel 23 and the effective rollers 34. This results in the indicated clockwise rotation of the carrier wheel 23 to its actuated position of FIGS. 2 and 6 wherein the axes of the bolts 42 and 44 are vertically aligned with the center of the carrier wheel 23.

From FIG. 5 it will be noted that only the lower group of five rollers 34 engages the housing ribs 33 to support the outer side frame 12 through the agency of the wheel 23 and suspension means 24. The peripheral slot 39 in wheel 23 in effect separates the two groups of rollers 34 and it will be observed that as the abovedescribed clockwise rotation of wheel 23 takes place from its latched active position, the lead roller 34 of the initially upper group of four rollers enters the trackway defined by ribs 33 and arcuate grooves 31 while some, preferably the last three, of the group of five rollers still are engaged therein. And as the trailing roller of the group of five leaves the trackway 31, 33, the first three of the initially upper group of four rollers 34 will already be disposed in the trackway. The wheel 23 and its rollers 34 thus effectively support the outer portion of the frame from the suspension means 24 at all times, and the slot 39 being disposed between the two groups of rollers 34 accomplishes the novel function of transporting the line 26 from the exterior outrigger 25 between the housing 22 and suspension means 24 into the interior of the closed-head block 11.

It will be appreciated that after the bundle block 11 has served its purpose in stringing conductors and before hanging it from an insulating means in another stringing operation, manual rotation of the carrier wheel 23 in a counterclockwise direction from its'operated or working position of FIGS. 2 and 6 back to its active line-receiving position of FIGS. 1 and 5 maybe assisted by breaking the toggle of the vertically aligned axes of bolts 42 and 44 and the center of wheel 23 and exerting downward pressure on the outer end of the head bar means 17. Asthe wheel 23 is returned toits line-receiving position, the detent 47, 48 of the trigger 45 will fall by gravity and in response to spring 51 into its active full line position of FIG. 5 in engagement with the notch 49 in the wheel to latch the line-receiving mechanism in such active position.

In transferring a pulling line or the like from the exterior to the interior of the closed-head frame as described, it is important that it be deposited on the pulling line sheave l9 and be prevented from moving into either or any conductor stringing sheave 20'to insure centering of the running board (not shown) to prevent damage or breaking of the equipment and, more importantly, the conductors being strung. To this end, guard means indicated generally by reference numeral 52, are disposed in the throat of the closed-head frame 11 over, and in closely spaced relationship to, the conductor stringing sheaves 20. As best seen in FIGS. 3 and 4, each guard means comprises a mounting bracket 53 clampingly secured by two u-shaped bolts 54 that embrace the side frame 12 and the nuts 55 on the ends of the bolts which pass through suitable apertures in the mounting bracket. The latter provides spaced pads at each end that are apertured to receive pivot pins 56 on upper and lower spaced arms 57 of a guard housing 58. A coil spring 59 is connected at one end at 61 to the rear, inner edge portion of guard 58 and at its other end at 62 to the mounting bracket 53.

When in their normal operative positions of FIGS. 1 and 2 and as shown in full lines in FIG. 4, the guard means 52 are disposed interiorly of the closed-head block, or in the throat thereof, above the conductor stringing sheaves to prevent engagement of a line 26 with the latter when it is transferred into the interior of the block. The housing 58 of each guard means 52 is resiliently maintained in such operative position by its spring 59 since, as shown in FIG. 4, both end connecting points 61, 62 of the spring are disposed forwardly of the pivot point 56 of the housing. It will be appreciated that as a running board is pulled through the throat of the block, it will strike against the forward portions of the guard means 52 and swing them horizontally on their pivots 56 rearwardly out of the throat portion of the block. Such swinging of the guard means 52 will be completed by their springs 59 as soon as the longitudinal axes of the springs pass outwardly beyond the pivots 56. The guards 52 will thus be swung to their inoperative positions, as shown in broken lines in FIG. 4, and be resiliently retained therein by their springs 59.

It will be understood that while the illustrated embodiment shows the line-receiving means 22-24 as a part of the closed-head helicopter conductor stringing block 11, the invention may be made as an adapter and incorporated into any block by merely separating the side frame members from the upper frame member or head bar and inserting the strap means 21 at the inner side and mounting the instant line-receiving means 22-24 and outrigger at the outer side as illustrated.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing 6 description, and, it, will .be, apparent that various changes may be made in the form, construction and arrangement of the; parts without departing from. the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbeforedescribed being merely a preferred embodiment thereof.

lclaimz 1. Line-transferring means for connecting the upper end of an outer frame member and head bar means of a closed-head bundle conductor stringing block having a pulling line sheave and conductor stringing sheave means coaxially mounted therein, comprising a housing for attachment to the upper end of said outer frame member and defining an arcuate trackway, a carrier wheel having circumferentially disposed bearing means cooperating with said trackway to enable rotation of said wheel relative to said housing, whereby rotation of said wheel allows lateral transfer of the line from the exterior to the interior of said frame while continuously permitting a closed-head condition of the block during said line transfer, and suspension means depending from said head bar means for rotatably supporting said wheel.

2. In line-transferring means according to claim 1, a bore through saidcarrier wheel eccentrically disposed relative to said bearing means, said suspension means comprising strap means pivotally secured to said head -bar means and a pin extending through said bore to rotatably support said wheel.

3. In line-transferring means according to claim 2, latch and trigger mechanism for retaining said carrier wheel in active position, and a peripheral slot in said wheel for receiving a line when said wheel is in active position and guiding the same, upon rotation of said wheel, into the interior of said closed-head block, said latch and trigger mechanism being releasable by said line moving laterally into said slot.

4. Line-transferring means according to claim 3, wherein said latch and trigger mechanism comprises a peripheral notch in said wheel, a rotatable bearing on said trigger, and spring means urging said rotatable bearing into said notch.

5. In line-transferring means according to claim 3, guard means disposed interiorly of said closed-head block above said conductor stringing sheave means to prevent said line from being engaged therewith when it is transferred to the interior of the block.

6. Line-transferring means according to claim 5, wherein said guard means are pivotally mounted on vertical axes on said frame for rearward swinging to inoperative position by a running board passing through said frame.

7. A conductor stringing blocking having a transversely extending shaft rotatably supporting a pulling line sheave, comprising a frame including inner and outer side frame members supporting said shaft, head bar means pivotally secured to the upper end of said inner side frame member, and line-transferring means supportingly interconnecting the upper end of said outer side frame member and said head bar means and operable without disconnection therefrom to pass a line laterally from the exterior to the interior of said frame and thereby permitting a closed-head condition of the block during said line transfer.

8. A closed-head conductor stringing block according to claim 7, wherein said line-transferring means comprises a housing and a carrier wheel rotatably interconnected with each other.

9. A closed-head conductor stringing block according to claim 7, wherein said line-transferring means comprises a housing secured to the upper end of said outer frame member and defining an arcuate trackway, a carrier wheel having circumferentially disposed bearing means cooperating with said trackway to enable rotation of said wheel relative to said housing, and suspension means depending from said head bar means for rotatably supporting said wheel.

10. In a closed-head conductor stringing block according to claim 9, an outrigger secured at its lower end to said housing and extending upwardly and outwardly therefrom for receiving a line from an aerial device and directing the same into contact with said wheel.

1 1. A closed-head conductor stringing block according to claim 9, wherein said housing comprising two complementary parts on opposite sides, respectively, of said carrier wheel.

12. A closed-head conductor stringing block according to claim 9, wherein said suspension means comprises a pin rotatably supporting said carrier wheel eccentrically relative to said bearing means.

13. A conductor stringing block having a transversely extending shaft rotatably supporting a pulling line sheave, comprising a frame including inner and outer side frame members supporting said shaft, head bar means pivotally secured to the upper end of said inner side frame member, and line-transferring means supportingly interconnecting the upper end of said outer side frame member and said head bar means and operable without disconnection therefrom to pass a line laterally from the exterior to the interior of said frame, wherein said line-transferring means comprises a housing secured to the upper end of said outer frame member and defining an arcuate trackway, a carrier wheel having circumferentially disposed bearing means cooperating with said trackway to enable rotation of said wheel relative to said housing, and suspension means depending from said head bar means for rotatably supporting said wheel, wherein said carrier wheel is provided with a peripheral slot for receiving a line and guiding the same laterally through said linetransfern'ng means into the interior of said frame in response to rotation of said wheel.

14. In a closed-head conductor stringing block according to claim 13, latch and trigger mechanism for retaining said carrier wheel in active position with said slot extending upwardly and outwardly and releasable by a line moving laterally into said slot to permit rotation of said wheel.

15. A closed-head conductor stringing block according to claim 14, wherein said latch and trigger mechanism comprises a notch in said wheel and an arm pivotally mounted at its upper end on said head bar means and having detent means normally engaging said notch and a lower end traversing said slot for movement by a line moving into said slot to release said detent means from said notch.

16. In a closed-head conductor stringing block according to claim 15, an outrigger secured at its lower end to said housing and extending upwardly and outwardly therefrom for receiving said line and guiding the same into said slot to release said detent means, whereby said wheel is rotated by the weight of said block to deliver said line laterally into the interior of said frame.

17. In a closed-head conductor stringing block according to claim 16 having conductor stringing sheave means rotatably supported on said shaft outwardly of said pulling line sheave, guard means normally disposed in operative position interiorly of said frame to prevent said line from being engaged therewith then it is transferred to the interior of the block.

18. A closed-head conductor stringing block according to claim 17, wherein said guard means are pivotally mounted on vertical axes on said frame for rearward horizontal swinging to inoperative position by a running board passing through said frame.

19. In a closed-head conductor stringing block according to claim 18, spring means interconnecting said guard means and said frame for resiliently retaining said guard means in both operative and inoperative positions. 

1. Line-transferring means for connecting the upper end of an outer frame member and head bar means of a closed-head bundle conductor stringing block having a pullIng line sheave and conductor stringing sheave means coaxially mounted therein, comprising a housing for attachment to the upper end of said outer frame member and defining an arcuate trackway, a carrier wheel having circumferentially disposed bearing means cooperating with said trackway to enable rotation of said wheel relative to said housing, whereby rotation of said wheel allows lateral transfer of the line from the exterior to the interior of said frame while continuously permitting a closed-head condition of the block during said line transfer, and suspension means depending from said head bar means for rotatably supporting said wheel.
 2. In line-transferring means according to claim 1, a bore through said carrier wheel eccentrically disposed relative to said bearing means, said suspension means comprising strap means pivotally secured to said head bar means and a pin extending through said bore to rotatably support said wheel.
 3. In line-transferring means according to claim 2, latch and trigger mechanism for retaining said carrier wheel in active position, and a peripheral slot in said wheel for receiving a line when said wheel is in active position and guiding the same, upon rotation of said wheel, into the interior of said closed-head block, said latch and trigger mechanism being releasable by said line moving laterally into said slot.
 4. Line-transferring means according to claim 3, wherein said latch and trigger mechanism comprises a peripheral notch in said wheel, a rotatable bearing on said trigger, and spring means urging said rotatable bearing into said notch.
 5. In line-transferring means according to claim 3, guard means disposed interiorly of said closed-head block above said conductor stringing sheave means to prevent said line from being engaged therewith when it is transferred to the interior of the block.
 6. Line-transferring means according to claim 5, wherein said guard means are pivotally mounted on vertical axes on said frame for rearward swinging to inoperative position by a running board passing through said frame.
 7. A conductor stringing blocking having a transversely extending shaft rotatably supporting a pulling line sheave, comprising a frame including inner and outer side frame members supporting said shaft, head bar means pivotally secured to the upper end of said inner side frame member, and line-transferring means supportingly interconnecting the upper end of said outer side frame member and said head bar means and operable without disconnection therefrom to pass a line laterally from the exterior to the interior of said frame and thereby permitting a closed-head condition of the block during said line transfer.
 8. A closed-head conductor stringing block according to claim 7, wherein said line-transferring means comprises a housing and a carrier wheel rotatably interconnected with each other.
 9. A closed-head conductor stringing block according to claim 7, wherein said line-transferring means comprises a housing secured to the upper end of said outer frame member and defining an arcuate trackway, a carrier wheel having circumferentially disposed bearing means cooperating with said trackway to enable rotation of said wheel relative to said housing, and suspension means depending from said head bar means for rotatably supporting said wheel.
 10. In a closed-head conductor stringing block according to claim 9, an outrigger secured at its lower end to said housing and extending upwardly and outwardly therefrom for receiving a line from an aerial device and directing the same into contact with said wheel.
 11. A closed-head conductor stringing block according to claim 9, wherein said housing comprising two complementary parts on opposite sides, respectively, of said carrier wheel.
 12. A closed-head conductor stringing block according to claim 9, wherein said suspension means comprises a pin rotatably supporting said carrier wheel eccentrically relative to said bearing means.
 13. A conductor stringing block haVing a transversely extending shaft rotatably supporting a pulling line sheave, comprising a frame including inner and outer side frame members supporting said shaft, head bar means pivotally secured to the upper end of said inner side frame member, and line-transferring means supportingly interconnecting the upper end of said outer side frame member and said head bar means and operable without disconnection therefrom to pass a line laterally from the exterior to the interior of said frame, wherein said line-transferring means comprises a housing secured to the upper end of said outer frame member and defining an arcuate trackway, a carrier wheel having circumferentially disposed bearing means cooperating with said trackway to enable rotation of said wheel relative to said housing, and suspension means depending from said head bar means for rotatably supporting said wheel, wherein said carrier wheel is provided with a peripheral slot for receiving a line and guiding the same laterally through said linetransferring means into the interior of said frame in response to rotation of said wheel.
 14. In a closed-head conductor stringing block according to claim 13, latch and trigger mechanism for retaining said carrier wheel in active position with said slot extending upwardly and outwardly and releasable by a line moving laterally into said slot to permit rotation of said wheel.
 15. A closed-head conductor stringing block according to claim 14, wherein said latch and trigger mechanism comprises a notch in said wheel and an arm pivotally mounted at its upper end on said head bar means and having detent means normally engaging said notch and a lower end traversing said slot for movement by a line moving into said slot to release said detent means from said notch.
 16. In a closed-head conductor stringing block according to claim 15, an outrigger secured at its lower end to said housing and extending upwardly and outwardly therefrom for receiving said line and guiding the same into said slot to release said detent means, whereby said wheel is rotated by the weight of said block to deliver said line laterally into the interior of said frame.
 17. In a closed-head conductor stringing block according to claim 16 having conductor stringing sheave means rotatably supported on said shaft outwardly of said pulling line sheave, guard means normally disposed in operative position interiorly of said frame to prevent said line from being engaged therewith then it is transferred to the interior of the block.
 18. A closed-head conductor stringing block according to claim 17, wherein said guard means are pivotally mounted on vertical axes on said frame for rearward horizontal swinging to inoperative position by a running board passing through said frame.
 19. In a closed-head conductor stringing block according to claim 18, spring means interconnecting said guard means and said frame for resiliently retaining said guard means in both operative and inoperative positions. 